mineral
Tumbled green aventurine
Quartz (SiO₂) with fuchsite or other mica inclusions
AI-generated identification · may be incorrectMohs hardness 6.5–7; translucent to opaque green, vitreous-to-waxy luster, granular microcrystalline quartz, with possible subtle aventurescence (sparkling reflections). No obvious cleavage; specific gravity about 2.6–2.7.
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Physical properties
Mohs hardness 6.5–7; translucent to opaque green, vitreous-to-waxy luster, granular microcrystalline quartz, with possible subtle aventurescence (sparkling reflections). No obvious cleavage; specific gravity about 2.6–2.7.
Formation & geological history
Forms when silica-rich fluids crystallize as quartzite or massive quartz containing chromium-bearing fuchsite mica; commonly Precambrian to younger metamorphic hydrothermal material. The pictured piece is polished/tumbled.
Uses & applications
Used for inexpensive beads, carvings, cabochons, ornaments, and decorative stone; generally a low-value gemstone.
Geological facts
Green color is typically caused by fuchsite mica, though some material is colored by chromium-bearing minerals. Aventurine is named for its glittering effect, from Italian *a ventura* (“by chance”).
Field identification & locations
Identify by its opaque apple-to-forest-green color, quartz-like hardness, and occasional mica sparkle; it should scratch glass but not quartz. Common sources include India, Brazil, Russia, Tanzania, and Zimbabwe.
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